Re: [PATCH] net: dsa: avoid null pointer dereference on p->phy
From: Joe Perches <joe@perches.com>
Date: 2017-09-23 17:13:12
Also in:
kernel-janitors, lkml
On Sat, 2017-09-23 at 17:57 +0100, Colin King wrote:
quoted hunk ↗ jump to hunk
From: Colin Ian King <redacted> Currently p->phy is being null checked in several places to avoid null pointer dereferences on p->phy, however, the final call to phy_attached_info on p->phy when p->phy will perform a null pointer dereference. Fix this by simply moving the call into the previous code block that is only executed if p->phy is not null. Detected by CoverityScan, CID#1457034 ("Dereference after null check") Fixes: 2220943a21e2 ("phy: Centralise print about attached phy") Signed-off-by: Colin Ian King <redacted> --- net/dsa/slave.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/net/dsa/slave.c b/net/dsa/slave.c index 02ace7d462c4..29ab4e98639b 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c@@ -1115,10 +1115,9 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev) of_phy_deregister_fixed_link(port_dn); return ret; } + phy_attached_info(p->phy); } - phy_attached_info(p->phy); - return 0; }
Huh? Why move this into the test?
The test of the block above this change is
if (!p->phy) {
Perhaps this should be
'
if (p->phy)
phy_attached_info(p->phy);
or simpler
} else {
phy_attached_info(p->phy);
}
or maybe reverse the block
if (p->phy) {
phy_attached_info(p->phy);
} else {
ret = dsa_slave_phy_connect(slave_dev, p->dp->index);
if (ret) {
netdev_err(slave_dev, "failed to connect to port %d: %d\n",
p->dp->index, ret);
if (phy_is_fixed)
of_phy_deregister_fixed_link(port_dn);
return ret;
}
}
return 0;
}